Unit for adjusting humidification

ABSTRACT

To provide a unit for adjusting humidification capable of improving inconveniences that may otherwise be caused to occur due to damages, while sustaining the humidifying ability and other performance that are to be originally achieved by the humidification adjusting unit. Around the outer surface of the exothermic member  13  are wound multiple hollow fibers  14  each having a minute diameter and having a peripheral wall with minute openings each being large enough to allow water vapor to permeate therethrough yet small enough to fail to permeate water therethrough, and the multiple hollow fibers  14  and the exothermic member  13  are inserted tightly into an extendable mesh cover tube  15  in engagement therewith. In order to perform humidification, water to be supplied to the multiple hollow fibers  14  is warmed by the exothermic member  13  to generate water vapors. Even if the multiple hollow fibers  14  would be broken or damaged, the water to be leaked from the multiple hollow fibers can be made extremely small in volume by taking advantage of the minuteness of each of the multiple hollow fibers  14 , thereby failing to cause to occur any substantial problems that may otherwise cause inconveniences due to the leakage of water.

[0001] This application is a divisional application of U.S. Ser. No.10/138,878, filed May 2, 2002, which is a divisional application of U.S.Ser. No. 09/230,010, filed Jan. 13, 1999, which was a U.S. nationalphase application of International Application Serial No.PCT/IB97/00849, filed Jul. 8, 1997.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a humidification unit, ahumidifying unit for an artificial respiratory device, and a method formanufacturing of a humidification unit.

[0004] 2. Description of the Related Art

[0005] Japanese Patent Application Unexamined Publication No. 62-26, 076discloses a humidification unit that uses a gas permeable tube having aperipheral wall with minute openings defined in the wall. The openingsare large enough to allow water vapor to permeate through the peripheralwall yet small enough to prevent water from passing therethrough. Morespecifically, this humidification unit includes a gas permeable tubehaving a peripheral wall with minute openings that are arranged in sucha way that an electrically exothermic member having an inner diameter ofat least 3 mm or larger is disposed in this single gas permeable tube.During use, the gas permeable tube communicates with a water supplysource and is filled in with water. Water vapors are discharged from thegas permeable tube through the minute openings provided in theperipheral wall with the aid of heat generated from the electricallyexothermic member.

[0006] The humidification unit described above, however, has adisadvantage in that should the gas permeable tube break, anunacceptably large amount of water is likely to leak outside the tube.For example, in the case where such a humidification unit is employed ina patient circuit for an artificial respiratory device, a large quantityof leaking water from the gas permeable tube may become hazardous,especially if the leaked water causes a decrease in the humidifyingfunction or if the leaked water flows into the intake side of theartificial respiratory device, i.e., the side connected to a patient.

SUMMARY OF THE INVENTION

[0007] Accordingly, it is on object of the present invention to providea humidification unit that does not suffer from the shortcomings of theabove-described conventional humidification devices. It is a furtherobject to provide a humidification unit that is capable of minimizingleakage from the humidification unit shoult the unit be damaged whilestill sustaining the humidifying function.

[0008] The present invention has a another object to provide anartificial respiratory system using such a humidification unit.

[0009] Further, the present invention has an object to provide a methodfor manufacturing such a humidification unit.

[0010] In order to achieve these objects, the present invention providesa humidification unit comprising an exothermic member having an outersurface and a plurality of hollow fibers disposed on the outer surfaceof the exothermic member. Each hollow fiber has a peripheral wall withminute openings that are large enough to allow a gas, such as watervapor, to permeate therethrough, yet small enough to prevent a liquid,such as water, from passing therethrough.

[0011] Furthermore, in order to achieve the above objects, the presentinvention provides a humidification unit comprising an exothermic memberhaving an outer surface and a plurality of hollow fibers disposed on theouter surface of the exothermic member. Each hollow fiber has peripheralwall with minute openings that are large enough to allow a gas, such aswater vapor, to permeate therethrough, yet small enough to prevent aliquid, such as water, from passing therethrough. The exothermic memberand hollow fibers define a humidification element, which is coupled to ashort connection tube that is adapted to be detachably connected to apatient circuit in an artificial respiratory system. Providing a supportmember in the form of the connection tube to which the humidificationelement is attached, allows the entire assemble to be readily disposedinto the patient circuit.

[0012] In order to achieve the other objects as described herein above,the present invention provides an artificially respiratory system andmethod of using same that includes a pressure generator adapted togenerate a flow of breathing gas, a patient circuit coupled to thepressure generator for delivering the flow of breathing gas to thepatient, and a humidification unit disposed in the patient circuit. Thehumidification unit comprises an exothermic member having an outersurface and a plurality of hollow fibers disposed on the outer surfaceof the exothermic member. Each hollow fiber has peripheral wall withminute openings that are large enough to allow a gas, such as watervapor, to permeate therethrough, yet small enough to prevent a liquid,such as water, from passing therethrough. In a further embodiment, afluid supply source communicates with the multiple hollow fibers tosupply liquid thereto.

[0013] The above objects are also achieved by providing a method forpreparing a humidification unit that includes the steps of providing aplurality of hollow fibers, wherein each hollow fiber is defined by aperipheral wall having minute openings large enough to allow a gas topass therethrough, yet small enough to prevent a liquid from passingtherethrough, and winding the hollow fibers around an exothermic membersuch that the plurality of hollow fibers are disposed on the outersurface of the exothermic member. In a further embodiment, the pluralityof hollow fibers are arranged in a sheet, and the sheet of hollow fibersare wound around the exothermic member such that a longitudinal axis ofthe plurality of hollow fibers is substantially parallel to alongitudinal axis of the exothermic member. In a still furtherembodiment, the plurality of hollow fibers are arranged in a strip, andthe strip of hollow fibers are wound around the exothermic member inspiral fashion.

[0014] Because the plurality of hollow fibers disposed on the outersurface of the exothermic member define a humidification element with arelatively small diameter and because each hollow fiber has a peripheralwall with minute openings that are large enough to allow a gas topermeate therethrough, yet small enough to prevent a liquid from passingtherethrough, the humidification element can be disposed in a pathhaving a small diameter, and can still provide a significant humidifyingfunction by heating the multiple hollow fibers with the exothermicmember. Furthermore, even if a few of the hollow fibers are damaged,broken, etc., the humidifying function is not significantly compromised,and water leaking from the humidification element is minimized. Inaddition, the exothermic member supports the multiple hollow fibers sothat the entire unit can be transported and handled relatively easily.

[0015] By providing an exothermic member that consists of anelectrically controlled exothermic member, the amount of heat to beapplied to the water in the multiple hollow fibers can be controlled,without waste and with a high degree of precision. Accordingly, thehumidification unit according to the present invention can ensurereliability and stability in its humidifying function.

[0016] By providing an exothermic member consisting of a heating wirefor generating heat upon transmission of electric current thereto, andby providing an electrically insulating member disposed around theheating wire for ensuring electrical insulation, the humidification unitcan ensure safety upon use, because the insulating performance can beensured even if an electrically powered exothermic member is employed asthe exothermic member.

[0017] On the other hand, by providing a heat pipe as the exothermicmember, the structure of the humidification unit can be simplified,because it does not require electrical insulation. Such a heat pipe alsoprovides support for the multiple hollow fibers held on the heat pipeemployed as the exothermic member.

[0018] Winding the multiple hollow fibers around the exothermic memberimproves the transmission of heat from the exothermic member to themultiple hollow fibers. In addition, the humidifying ability can bereadily increased or decreased by adjusting the amount of the multiplehollow fibers wound around the exothermic member.

[0019] In a further embodiment of the present invention, the ends themultiple hollow fibers are joined together and a connector is providedfor connecting the fibers to a fluid source. In a still furtherembodiment, the connector to the supply of fluid is located on only oneend of the fibers, thereby simplifying the use of the humidificationunit so that only one fluid connection is required. In anotherembodiment, however, both ends of the multiple hollow fibers areconnected to the fluid supply source to allow fluid to be supplied toboth ends of the multiple hollow fibers so that the supply of fluid toeach of the multiple hollow fibers can be performed at a high speed andwith high precision. Also, should one supply of fluid fail or becomeblocked, the other serves as a backup.

[0020] If the multiple hollow fibers are joined at one end portion,which is the same as the side of the electric current supply end of theexothermic member, the electric current supply system and the watersupply system can be concentrated at one location.

[0021] These and other objects, features and characteristics of thepresent invention, as well as the methods of operation and functions ofthe related elements of structure and the combination of parts andeconomies of manufacture, will become more apparent upon considerationof the following description and the appended claims with reference tothe accompanying drawings, all of which form a part of thisspecification, wherein like reference numerals designate correspondingparts in the various figures. It is to be expressly understood, however,that the drawings are for the purpose of illustration and descriptiononly and are not intended as a definition of the limits of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a structural diagram showing a humidifying unit for anartificial respiratory device according to a first embodiment of thepresent invention;

[0023]FIG. 2 is a diagram showing an enlarged portion of the humidifyingunit of FIG. 1;

[0024]FIG. 3 is a perspective view showing a humidifying elementemployed in the humidifying unit of FIG. 1;

[0025]FIG. 4 is a cross-sectional view of a connector for thehumidifying unit of FIG. 1;

[0026]FIG. 5 is a perspective view illustrating a step in thepreparation of the humidifying unit of FIG. 1;

[0027]FIG. 6 is a perspective view illustrating a further step in thepreparation of the humidifying unit of FIG. 1;

[0028]FIG. 7 is a perspective view illustrating a still further step inthe preparation of the humidifying unit of FIG. 1;

[0029]FIG. 8 is a perspective view showing a humidifying elementaccording to a second embodiment of the present invention;

[0030]FIG. 9 is a perspective view showing a humidifying elementaccording to a third embodiment of the present invention;

[0031]FIG. 10 is a perspective view showing a humidifying elementaccording to a fourth embodiment of the present invention;

[0032]FIG. 11 is a perspective view showing the multiple hollow fibersarranged in a strip according to the fourth embodiment of the presentinvention;

[0033]FIG. 12 is a cross-sectional view showing the multiple hollowfibers wound around the exothermic member;

[0034]FIG. 13 is a perspective view showing a humidifying elementaccording to a fifth embodiment of the present invention;

[0035]FIG. 14 is a perspective view showing the humidifying elementaccording to a sixth embodiment of the present invention;

[0036]FIG. 15 is a perspective view showing the humidifyng elementaccording to a seventh embodiment of the present invention;

[0037]FIG. 16 is a perspective view showing the humidifying elementaccording to an eighth embodiment of the present invention;

[0038]FIG. 17 is a perspective view showing the humidifying elementaccording to a ninth embodiment of the present invention; and

[0039]FIG. 18 is a perspective view showing the humidifying elementaccording to a tenth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS OF THEINVENTION

[0040] The present invention will be described by way of examples withreference to the accompanying drawings. FIGS. 1 to 7 show thehumidification unit according to a first embodiment of the presentinvention. As shown in FIG. 1, reference numeral 1 denotes a patientcircuit in an artificial respiratory device suitable for connecting anadapter (not shown), which is connected to the lungs of a patient, to asource of breathing gas. An inner portion of patient circuit 1constitutes an intake path 2 for the delivery of breathing gases to anairway of the patient from a supply of breathing gas, such as a pressuregenerator. The flow of breathing gas in patient circuit 1 is indicatedby arrow 3. The inner diameter of patient circuit 1 may be set to be inthe range of, for example, from 14 mm to 16 mm for an infant patient andfrom 20 mm to 24 mm for an adult patient.

[0041] In the embodiment shown in FIGS. 1 and 2, patient circuit 1 ismounted detachably to a humidification unit 4 that is provided with ashort connection tube 5 as a support member, a mounting flange 6, and ahumidifying element 7. Connection tube 5 may be a straight tube withboth end portions engaged (connected) in an airtight fashion toconnection end portions 1 a of patient circuit 1. The outer diameter ofconnection tube 5 is set so as to be somewhat larger than the innerdiameter of patient circuit 1, in order to ensure the airtightengagement with patient circuit 1 to be connected thereto, and it may beset appropriately in accordance with the patient circuit to be employed.As a matter of course, in this case, the relationship of engagement ofconnection tube 5 with connection end portions 1 a of patient circuit 1may be such that the inner periphery of connection tube 5 is engagedwith the outer periphery of connection end portions 1 a of patientcircuit 1. In such a case, the inner diameter of connection tube 5 isset to be somewhat smaller than the outer diameter of connection endportions 1 a of patient circuit 1 to be connected thereto, in order toensure the airtight engagement with patient circuit 1 to be connectedthereto. Further, in this case, the use of a packing, a fastening bandor the like may be employed in order to enhance airtightness.

[0042] The peripheral wall on one end of connection tube 5 (e.g., on theleft side in FIGS. 1 and 2) is formed with a mounting opening 8 formounting flange 6. Mounting opening 8 is located at a position outsideof connection end portion 1 a of patient circuit 1 upon connection withconnection end portion 1 a and disposed so as to allow the inside ofconnection tube 5 to communicate with the outside thereof.

[0043] In the illustrated exemplary embodiment, mounting flange 6consists of a flange portion 6 a in a square-plate shape or the like anda cylindrical holding portion 6 b. Flange portion 6 a of mounting flange6 is shaped so as to be disposed along an outer peripheral wall ofconnection tube 5 and it is fixed to connection tube 5 by a screw 9 soas to cover the mounting opening 8 of connection tube 5 in a tightmanner. Flange portion 6 a is further provided with a communicatingopening 10 that allows mounting opening 8 of connection tube 5 to opento the outside in the center of flange portion 6 a.

[0044] Holding portion 6 b of mounting flange 6 is disposed so as tostand upright with respect to the plate surface of flange portion 6 a,such that opening 10 of flange portion 6 a faces an opening 11 at thebase end thereof. Holding portion 6 b is arranged so as to insertthrough mounting opening 8 of connection tube 5 over the entire lengthof mounting opening 8 of connection tube 5, extending up to the centerof connection tube 5 in the radial direction, and then curved on theother end side of connection tube 5 at a generally right angle (on theright end side in FIGS. 1 and 2). An opening 12 is defined in holdingportion 6 b so as to face an open end of connection tube 5. Opening 12at one end of holding portion 6 b is large enough to engage and holdhumidifying element 7, and opening 12 is arranged so as to communicateto the outside through communicating opening 10 of flange portion 6 a inholding portion 6 b.

[0045] As shown in FIG. 3, humidifying element 7 comprises exothermicmember 13, multiple hollow fibers 14 held at the outer surface ofexothermic member 13, and a mesh cover tube 15 covering exothermicmember 13 and multiple hollow fibers 14. In this embodiment of thepresent invention, exothermic member 13 is an electrically poweredexothermic member of a columnar shape and has a diameter in the rangeof, for example, from approximately 3 mm to 6 mm, and an entire lengthin the range of, for example, from approximately 1 m to 2 m. The lengthin left-hand and right-hand directions in FIGS. 1 and 2) of exothermicmember 13 is shorter that the axial length of connection tube 5.Exothermic member 13 comprises a heating wire 16 (a heater wire) and anelectrically insulating member 17 enclosing the periphery of heatingwire 16. Heating wire 16 is disposed in the inside of electricallyinsulating member 17 and has the function of generating heat uponreceiving an electric current. A connection cord 18 is connected toheating wire 16 and extends from one end of exothermic member 13. An endportion of connection cord 18 is provided with a connector 19 forsupplying electric current to the heating wire.

[0046] Each hollow fiber constituting the multiple hollow fibers 14 hasa peripheral wall with minute openings (for example, a porosity rate ofapproximately 57.8%) which allows a gas, such as water vapor, topermeate therethrough, yet prevents a liquid, such as water, frompassing therethrough. Each hollow fiber is minute in size (for example,having an outer diameter of 413 microns, an inner diameter of 282microns, and an entire length of approximately 1.2 meters-1.5 meters).In one embodiment of the present invention, the multiple hollow fibers(the total number of from 40 to 60 hollow fibers in this embodiment) aredisposed such that the axis of each hollow fiber 14 is nearly parallelto the longitudinal axis of exothermic member 13 and the entireperiphery of exothermic member 13 is covered with multiple hollow fibers14. In this embodiment, multiple hollow fibers 14 are folded not rolledin the direction in which they extend, and exothermic member 13 iscovered with the folded multiple hollow fibers. The end portions ofmultiple hollow fibers 14 is arranged so as to extend outward from theends of the exothermic member 13.

[0047] As shown in FIGS. 3 and 4, the end portions of multiple hollowfibers 14 are joined together at a position outside of either end ofexothermic member 13 via an adhesive agent 20 into a bundled state. Thebundled portion is formed with a connector 21 having a given shape forsupplying water to the hollow fibers. Upon forming connector 21,adhesive agent 20 may penetrate into the inside of the multiple hollowfibers 14 so that the end portion of the bundled multiple hollow fibers14 into which the adhesive agent has penetrated can be cut in roundslices to form a new end surface. Connection cord 18 is disposed so asto extend through multiple hollow fibers 14.

[0048] As shown in FIG. 3, mesh cover tube 15 is in a mesh that extendsin both its axial and radial directions. Mesh cover tube 5 has anopening extending axially over the entire length and communicating theinside to the outside thereof. Exothermic member 13 and multiple hollowfibers 14 wound around the outer surface of exothermic member 13 areinserted into mesh cover tube 15 in a tight fashion. Multiple hollowfibers 14 are allowed to press against the outer surface of exothermicmember 13 by an appropriate degree of pressing force that is created bythe force due to the contraction of mesh cover tube 13.

[0049] Humidifying element 7 mainly has an extended shape depending uponthe shape of exothermic member 13 and it is shaped such that thediameter of the humidifying element is smaller than the inner diameterof connection tube 5 and such that the length is shorter than the axiallength of connection tube 5. Humidifying element 7 is arranged so as tobe accommodated in its entirety within connection tube 5.

[0050] The end portion (the left end portion in FIGS. 1 and 2) ofhumidifying element 7 is held in a tight engagement with the end portionof holding portion 6 b of mounting flange 6 in connection tube 5. On theother hand, the other end portion (the right end portion in FIGS. 1 and2) of humidifying element 7 is a free end and extends toward the otherend of connection tube 5. Further, the connection cord 18 and multiplehollow fibers 14 extend from holding portion 6 b toward the outside ofmounting flange 6 through communicating opening 10. Connector 21 andconnector 19 are located outside of mounting flange 6.

[0051] Humidifying element 7 may be prepared in the steps as shown inFIGS. 5 to 7. As shown in FIG. 5, first, multiple hollow fibers 14, eachhaving the peripheral wall with minute openings that are large enough toallow water vapor to permeate therethrough, yet small enough to preventwater from passing therethrough, are prepared so as to be formed into asheet in which the axis of the multiple hollow fibers 14 are arranged soas to be generally parallel to each other. By combining the multiplehollow fibers in the manner as described herein above, the multiplehollow fibers can be treated in a collective manner, thereby making itrelatively easy to attach the multiple hollow fibers to exothermicmember 13. In this case, a string member 23 or the like may be employedto join multiple hollow fibers 14 integrally to each other into thesheet of multiple hollow fibers.

[0052] Then, as shown in FIG. 5, multiple hollow fiber sheet 22 a isfolded in the lengthwise direction in which each of the multiple hollowfibers 14 extends, and exothermic member 13 is disposed within foldedmultiple hollow fiber sheet 22 a. At this time, the other end portion ofexothermic member 13 is arranged so as to be even with the foldedportion of multiple hollow fiber sheet 22 a, while attention is beingpaid to the fact that the folded portion of multiple hollow fiber sheet22 a is not squashed and that the axis of exothermic member 13 isarranged so as to be generally parallel to the axis of multiple hollowfibers 14. Further, both end portions of multiple hollow fibers 14 aredisposed so as to project outward from the one end portion of exothermicmember 13.

[0053] Thereafter, as shown in FIG. 6, folded multiple hollow fibersheet 22 a is wound around exothermic member 13. By holding multiplehollow fibers 14 to the outer surface of exothermic member 13 andarranging multiple hollow fibers 14 so as to increase the area ofexothermic member 13 in which multiple hollow fibers 14 are held toexothermic member 13, the humidifying ability of humidifying element 7(the humidification unit 4) is improved.

[0054] At this time, as shown in FIGS. 5 and 7, connection cord 18 isdisposed so as to extend through multiple hollow fibers 14 and projecttoward the outside of wound multiple hollow fiber sheet 22 a. Thisallows the work for forming connector 21 to be conducted with relativeeast in the step that follows.

[0055] Then, as shown in FIG. 7, multiple hollow fiber sheet 22 a andexothermic member 13 are inserted tightly into extendable mesh covertube 15. The multiple hollow fibers are held with high precision toexothermic member 13 and each of the multiple hollow fibers is incontact with exothermic member 13 with an appropriate degree of thepressing force, thereby improving the transmission of heat fromexothermic member 13 to multiple hollow fibers 14.

[0056] Next, as shown in FIGS. 3 and 4, the end portion of the foldedhollow fiber sheet 22 a is joined together with adhesive agent 20 into abundle. The bundled portion is formed with connector 21 to formhumidifying element 7. This does not require a connector to be preparedseparately and, therefore, reduces the number of parts. Further, thisconfiguration allows water to be supplied to multiple hollow fibers 14from both ends of the multiple hollow fibers 14, for example, therebyallowing each of multiple hollow fibers 14 to be filled with water at ahigh speed and with a high degree of precision.

[0057] Connector 21 may be formed by combining the end portions ofmultiple hollow fibers 14 together or by separately combining each ofthe end portions of multiple hollow fibers 14 together.

[0058] As shown in FIG. 1, connector 21 of humidifying element 7prepared in the manner as described herein above, is connected through awater supply tube 25 to a water bag 24 as a source of supplying water tothe hollow fibers. Water bag 24 is filled with a predetermined amount ofwater, and the amount of water in the water bag 24 can be visuallyconfirmed, because water bag 24 is made of a transparent or translucentmaterial. Water bag 24 is mounted on a pole (not shown). Water bag 24 isfurther provided with a water outlet 24 a at its lower portion and withan opening (not shown) at its upper portion through which the inside ofthe bag communicates to the outside.

[0059] Water supply tube 25 has one end portion connected (for example,held by engagement) to water outlet 24 a of water bag 24 and another endportion formed with a connector 26 (schematically shown) as thecounterpart of connector 21, as shown in FIGS. 1 and 4. Connector 26 isformed so as to engage connector 21 in an airtight manner by a one-touchoperation.

[0060] Further, as shown in FIG. 1, water supply tube 25 is providedwith a water drop counting device 27 as a flow meter for measuring theflow of water therethrough. The water drop counting device 27 isarranged so as to allow a flow of water to multiple hollow fibers 14after the water has been dropped from water bag 24 into the water dropcounting device 27. Further, water drop counting device 27 is arrangedso as to visually confirm the state in which the water drops.

[0061] Connected to connector 19, as shown in FIG. 1, is anotherconnector 28 for supplying of electric current to exothermic number 13.The other end of electric connector 28 is connected to a power source 30through an adjustment unit 29. By connecting connectors 19 and 28,electric current is allowed to be supplied to heating wire 16, therebygenerating heat and warming each of the multiple hollow fibers 14 tocause them to discharge water vapor into the flow of breathing gas 3from multiple hollow fibers 14. The amount of the water vapor dischargedmay be adjusted automatically on the basis of the difference between thepressure of the water vapor in multiple hollow fibers 14 and thepressure of the water vapor in patient circuit 1.

[0062] It can be appreciated that the temperature of the flow ofbreathing gas can be controlled by the exothermic member 13 so as toremain below a predetermined temperature, that is, a temperature atwhich inconveniences may be caused to occur for the patient.

[0063] In FIG. 1, reference symbol M denotes a monitor. In theillustrated embodiment, monitor M is supplied on the downstream side ofhumidification unit 4 with signals from a temperature-moisture sensor 31for sensing the temperature and the moisture of the flow of breathinggas and signals from a water drop detecting sensor 32 for sensing waterdrops in the water dropping device 27. Monitor M monitors these signalsand operates an alarm (for example, an alarm lamp or an alarm buzzer) ifthe monitored characteristic becomes higher than a set level.

[0064] Therefore, humidifying system 34, with the structure as describedherein above, as a matter of course, humidifies the flow of breathinggas to an appropriate extent by discharging water vapors fromhumidifying element 7 when humidifying element 7 is disposed in patientcircuit 1. Further, humidifying system 34 is adapted so as to monitorthe breakage of hollow fibers 14 or other damages (i.e., a leakage ofwater from hollow fibers 14) with extremely high precision, because thewater drop detecting sensor can sense the leakage of water, even if verysmall, from hollow fibers 14 due to the breakage or damage of the hollowfibers as a variation in the flow of water drops through water droppingunit 27 (i.e., whether the set flow rate is satisfied), and the detectedflow is transmitted to monitor M and then to alarm 33.

[0065] Furthermore, in this embodiment of the present invention, inaddition to the contents as described herein above, multiple hollowfibers 14 are each extremely small in diameter. Therefore, even ifhollow fibers 14 are broken or damaged or undergo other faults, theamount of water leaking from hollow fibers 14 can be minimized to anextremely small level, so that the humidifying ability of thehumidifying unit according to the present invention is not significantlyreduced and the inconveniences and problems which may otherwise becaused due to the leakage of water are also minimized.

[0066] In this case, although multiple hollow fibers 14 are generallyflexible, they are held on exothermic member 13 that is physicallystronger, so that exothermic member 13 provides function of supportingflexible hollow fibers 14. Therefore, multiple hollow fibers 14 canalways sustain their predetermined shape without requiring a separatesupporting means by taking advantage of exothermic member 13 as a unitfor holding the shape of multiple hollow fibers 14.

[0067] Further, exothermic member 13 has a columnar shape extending inboth directions so that the area of the exothermic member for heatingthe multiple hollow fibers and the area thereof for holding them can beincreased rapidly, thereby enabling improvements in the humidifyingability and enhancing the ability of holding the shape of multiplehollow fibers 14.

[0068] Furthermore, as exothermic member 13 consists of electricallypowered exothermic member, the amount of heating of multiple hollowfibers 14 (i.e., the water contained herein) can be controlled withoutwaste and with high precision, thereby providing reliability and safetyfor the humidifying ability of the humidification unit 4 according tothe present invention.

[0069] In this case, there is provided electrically insulating member 17enclosing the heating wire 16 for ensuring electrical insulation. Thus,even if an electrically powered exothermic member is employed asexothermic member 13, safety during use can be ensured.

[0070] Furthermore, multiple hollow fibers 14 are wound aroundexothermic member 13 in such a manner that the axis of each of hollowfiber is arranged so as to be generally parallel to the axis ofexothermic member 13, thereby ensuring a secure contact of each hollowfiber with the outer surface of exothermic member 13, thereby improvingthe transmission of heat to each hollow fiber from exothermic member 13.In addition, the amount of multiple hollow fibers 14 wound aroundexothermic member 13 can be readily adjusted, thereby allowing a readyincrease or a decrease of the humidifying ability of the humidificationunit according to the present invention.

[0071] In addition, multiple hollow fibers 14 are bundled (joined)outside one end of the exothermic member 13 and formed with connector 21for connection to water bag 24. Therefore, the humidification unitaccording to the present invention minimizes the number of parts,because such a connector is not required to be prepared separately.

[0072] Further, connector 21 for supplying water is located on one endof exothermic member 13. By using one end of exothermic member 13 as theside for supporting a mounting object, the supporting system, the watersupply system, and the electric current supply system of thehumidification unit 4 according to the present invention can beconcentrated at one location, thereby simplifying the manner of use andthe structure of connection and making the connection more efficient.

[0073] On the other hand, each of the multiple hollow fibers can also befilled with water at a high speed and with high precision by supplyingwater to the multiple hollow fibers 14 from both ends. As the peripheralwall of each of the multiple hollow fibers 14 is provided with minuteopenings that are each large enough to allow water vapor to permeatetherethrough, yet small enough to fail to permeate water therethrough,air present in each of the multiple hollow fibers 14 can be dischargedthrough the minute openings formed in the peripheral walls of themultiple hollow fibers as the water is supplied thereto. Hence, each ofthe multiple hollow fibers 14 can always be filled in with water withoutthe presence of air therein.

[0074] Furthermore, even if one end of the multiple hollow fibers shouldbe blocked, water can still be supplied to the multiple hollow fibers 14form the other end. This arrangement, therefore, enhances thereliability of the water supply to each of the multiple hollow fibers.

[0075] Further, in this embodiment of the present invention,humidification unit 4 is provided with connection tube 5 having astraight tube shape so that it can be readily set in place in patientcircuit 1 simply by connecting connection tube 5 to connection endportion 1 a of patient circuit 1. This improves ease of setting thehumidification unit in place.

[0076] In addition, because humidifying element 7 is combined in a unit,the assembly of the humidifying element with connection tube 5 can beperformed in a simplified manner using mounting flange 6. Further, thehumidifying element can be assembled directly with patient circuit 1 ina simplified manner by forming the mounting opening 8 in the patientcircuit 1.

[0077] Further, as humidifying element 7 is accommodated in connectiontube 5 in its entirety, the humidifying element is protected by theconnection tube, whereby the mounting operation, the transferringoperation and other operations can be carried out in a convenientmanner.

[0078] In addition, as exothermic member 13 and multiple hollow fibers14 are inserted into extendable mesh cover tube 15 in a tightly engagedmanner, the multiple hollow fibers can be held around the exothermicmember with high precision and the transmission of heat from theexothermic member to each of the multiple hollow fibers can be improved,by allowing each of the multiple hollow fibers to come into contact withthe exothermic member with an appropriate degree of pressing force.

[0079] FIGS. 8 et seq, show other embodiments of the humidification unitaccording to the present invention. In each of the embodiments thatfollow, the same structuring elements as in the first embodiment areprovided with the identical reference numerals and symbols and aduplicate description will be omitted.

[0080]FIG. 8 shows the humidification unit according to a secondembodiment of the present invention. In the second embodiment, multiplehollow fibers 14 are bundled (joined) at both ends of the exothermicmember 13 and the bundled portions are formed each with connector 21 tobe connected to water bag 24.

[0081] The humidification unit according to this embodiment can reducethe number of parts because a connector is not required to be preparedseparately. Further, water can be filled in each of the multiple hollowfibers at a high speed and with high precision, because the water issupplied to each of the multiple hollow fibers from both ends thereof.In addition, even if multiple hollow fibers 14 would be blocked at theconnector on either side of exothermic member 13, water can still besupplied to each of the multiple hollow fibers from the other connector,thereby enhancing the reliability in supplying water to each of themultiple hollow fibers.

[0082]FIG. 9 shows a humidification unit according to a third embodimentof the present invention. In the third embodiment, multiple hollowfibers 14 are bundled (joined) on the side of exothermic member 13opposite the electric current supply side of the exothermic member 13and the bundled portion is formed with connector 21 to be connected towater bag 24. This arrangement allows connector 21 to be formed withouttaking an electric current supply system into consideration, therebymaking the formation of connector 21 easier.

[0083] Of course, the present invention contemplates that connector 21may be formed on the same side of exothermic member 13 to which electriccurrent supply is connected.

[0084] FIGS. 10-12 show a humidification unit according to a fourthembodiment of the present invention. In the fourth embodiment, minuteopenings are provided in multiple hollow fibers 14, each opening beinglarge enough to allow water vapor to permeate therethrough, yet smallenough to fail to permeate water therethrough. The multiple hollowfibers are formed into a strip 22 b by connecting each of multiplehollow fibers 14 integrally to each other with a string member 23 or thelike as shown. Multiple hollow fiber strip 22 b is then wound aroundexothermic member 13 in a spiral manner, and humidifying element 7 isthen prepared by inserting multiple hollow fiber strip 22 b andexothermic member 13 into extendable mesh cover tube 15 in a tightlyengaged manner.

[0085] In the preparation of the humidifyng element in the manner asdescribed herein above, there can also be achieved the action andeffects similar to those as achieved by the method for the preparationof the humidification unit in the first embodiment of the presentinvention.

[0086] In the fourth embodiment of the present invention, as shown inFIG. 10, the multiple hollow fiber strip 22 b is wound around exothermicmember 13, starting with a one end portion of the exothermic member,over the entire length thereof to the other end portion thereof and thencontinually turning from the other end portion thereof back to the oneend portion thereof. Winding of multiple hollow fiber strip 22 b aroundexothermic member 13 in this manner locates both end portions ofmultiple hollow fibers strip 22 b at the one end portion of exothermicmember 13 and both end portions of multiple hollow fibers strip 22 b areformed with one connector 21. As a matter of course, at this time, bothend portions of the multiple hollow fibers gathering 22 b can be bundledtogether integrally and the bundled portion may be formed with oneconnector 21.

[0087] In the fourth embodiment of the present invention, the amount ofmultiple hollow fibers 14 held on exothermic member 13 can be increased,thereby improving the humidifying ability. At the same time, as both endportions of multiple hollow fiber strip 22 b are located at one endportion of exothermic member 13, the humidification unit according tothe fourth embodiment of the present invention can achieve the actionand effects equivalent of those as achieved in the first embodiment(FIG. 3).

[0088]FIG. 13 shows a humidification unit according to a fifthembodiment of the present invention and specifically shows a variant ofthe manner of winding multiple hollow fiber strip 22 b around exothermicmember 13. In the fifth embodiment, multiple hollow fiber strip 22 b iswound around exothermic member 13 starting with a one end portion ofexothermic member 13 and extending over the entire length up to theother end portion of the exothermic member in a manner such that the oneend portion of multiple hollow fiber strip 22 b is located at the oneend portion of the exothermic member and the other end portion of themultiple hollow fiber strip is located at the other end portion of theexothermic member. Further, the openings at end portion 35 of strip 22 bare closed with adhesive agent or the like (the openings at end portion35 of multiple hollow fiber strip 22 b are closed is shown by obliquelines in the drawing). Furthermore, one end portion of multiple hollowfiber strip 22 b is bundled (joined) and the bundled portion is formedwith connector 21.

[0089] As multiple hollow fiber strip 22 b is wound around theexothermic member 13 in a spiral form in the manner as described hereinabove, even where connector 21 is to be located at one side ofexothermic member 13 that is the same and where the electric currentsupply is provided to exothermic member 13, connector 21 can be formedwithout taking the electric current supply system into consideration,thereby facilitating the preparation of connector 21.

[0090]FIG. 14 shows a humidification unit in accordance with a sixthembodiment of the present invention, which is a variant of the fifthembodiment as described herein above. In the sixth embodiment, one endportion of multiple hollow fiber strip 22 b, which is wound aroundexothermic member 13, is located at one end portion of the exothermicmember 13, and the other end portion of strip 22 b is located at theother end portion of the exothermic member 13. Further, multiple hollowfiber strip 22 b is bundled (joined) at each end portion thereof, andeach of the bundled portions is formed with a connector 21. Thisarrangement can achieve the action and effects equivalent of those asachieved by humidifying element 7 in the second embodiment.

[0091]FIG. 15 shows a humidification unit in accordance with a seventhembodiment of the present invention, which is a variant of thehumidification unit 4. In the humidification unit 4 of FIG. 15, mountingflange 6 is arranged in a manner such that holding portion 6 b′, isdisposed standing upright from flange portion 6 a and one end portion ofhumidifying element 7 is curved at a nearly right angle with respect tothe other end portion thereof. Further, one end portion of humidifyingelement 7 is held to holding portion 6 b′ by engagement therewith.

[0092] In this case, humidifying element 7 can be disposed with theother end portion thereof extending in the axial direction of connectiontube 5 by mounting mounting flange 6 on connection tube 5.

[0093]FIG. 16 shows a humidification unit in accordance with an eighthembodiment of the present invention. In the eighth embodiment,connection tube 5′ is a generally L-shaped tube and is disposed in sucha manner that one end portion of humidifying element 7 is mountedthrough mounting flange 6 on a first tube portion 5 a on one end ofconnection tube 5′ in a region where the end portion of humidifyingelement 7 faces a sectional surface of the path defined in a second tubeportion 5 b on the other side of connection tube 5′. The other end ofthe humidifying element 7 extends in an axial direction of second tubeportion 5 b on the other side of connection tube 5′ in second tubeportion 5 b.

[0094] This arrangement allows the generally L-shaped tube to bedetachably mounted to patient circuit 1 in the same manner as in thefirst embodiment described above. In this embodiment, first tube portion5 a on one side of the generally L-shaped tube 5′ can be employed as asupporting portion (a mounting portion) for supporting humidifyingelement 7 with high precision and further humidifying element 7 is setready for use simply by inserting humidifying element 7 into mountingopening 8 of connection tube 5′ at a right angle to the first tubeportion 5 a on one side of connection tube 5′.

[0095]FIG. 17 shows a humidification unit according to a ninthembodiment of the present invention, which is a variant of thehumidification unit according to the eighth embodiment as describedherein above. In the ninth embodiment, connection tube 5″ is of aninner-outer double tube structure. A second tube portion 5 b on one sideof connection tube 5″ is used as done in the eighth embodiment and maybe further employed as an inner tube 36 of the connection tube accordingto this embodiment. Inner tube 36 is disposed such that an outer tube 37encloses the outer periphery of inner tube 36, thereby forming aring-shaped path around and between an outer wall surface of the innertube and an inner wall surface of the outer tube.

[0096] In this embodiment, connection tube 5″ can be connected to anartificially respiratory circuit of an inner-outer double tube structureand the humidification unit according to this embodiment can be setreadily to such an artificially respiratory circuit. In this case,exhaled gases are allowed to flow on the side of the outer tube (betweenthe inner tube and the outer tube) and it is possible to prevent watervapors within the inner tube from condensing by using the heat from theexhaled gases flowing in the ring-shaped path.

[0097]FIG. 18 shows a humidification unit in a tenth embodiment of thepresent invention, which shows a variant of exothermic member 13. In thetenth embodiment, a heat pipe 38 is employed as the exothermic memberand a heater 39 is mounted on a one end portion of heat pipe 38.

[0098] This arrangement of the exothermic member can simplify thestructure of the humidification unit, because it is not necessary toensure insulation in a region where multiple hollow fibers 14 are heldand humidified. Further, using a general intensity member for heat pipe38, the position of the multiple hollow fibers 14 held to the heat pipecan be enhanced to a higher extent. Further, by using heater 39 as aheat source of an endothermic portion of heat pipe 38, the action of theheat pipe 38 as the exothermic member 13 can be ensured.

[0099] Although the invention has been described in detail for thepurpose of illustration based on what is currently considered to be themost practical and preferred embodiments, it is to be understood thatsuch detail is solely for that purpose and that the invention is notlimited to the disclosed embodiments, but, on the contrary, is intendedto cover modifications and equivalent arrangements that are within thespirit and scope of the appended claims.

1. A unit for adjusting humidification characterized in that anexothermic member is provided on an outer surface thereof with multiplehollow fibers each having a peripheral wall with minute openings each ofwhich is large enough to allow water vapor to permeate therethrough yetsmall enough to fail to permeate water therethrough.
 2. A unit foradjusting humidification as claimed in claim 1, characterized in thatsaid exothermic member is of an extendable form.
 3. A unit for adjustinghumidification as claimed in claim 2, characterized in that saidexothermic member is an electrically exothermic member.
 4. A unit foradjusting humidification as claimed in claim 3, characterized in thatsaid electrically exothermic member comprises heating wire capable ofgenerating heat upon transmission of electric current therethrough andan electrically insulating member disposed around said heating wire soas to ensure insulation.
 5. A unit for adjusting humidification asclaimed in claim 2, characterized in that said exothermic member is aheat pipe.
 6. A unit for adjusting humidification as claimed in claim 5,characterized in that said heat pipe is provided with a heater at a oneend thereof.
 7. A unit for adjusting humidification as claimed in claim2, characterized in that said exothermic member is wound with saidmultiple hollow fibers.
 8. A unit for adjusting humidification asclaimed in claim 7, characterized in that said multiple hollow fibersare wound around said exothermic member in a spiral manner.
 9. A unitfor adjusting humidification as claimed in claim 7, characterized inthat said multiple hollow fibers are wound around said exothermic memberin such a manner that the axis of each of said multiple hollow fibers isarranged so as to be nearly parallel to the axis of said exothermicmember.
 10. A unit for adjusting humidification as claimed in claim 2,characterized in that said multiple hollow fibers are bundled togetherat either of their sides of said exothermic member and that a bundledportion of said multiple hollow fibers is formed with a connector to beconnected to the side of a water supply source.
 11. A unit for adjustinghumidification as claimed in claim 2, characterized in that saidmultiple hollow fibers are bundled together at each of their both sidesof said exothermic member and that each of bundled portions of saidmultiple hollow fibers is provided with a connector to be connected tothe side of a water supply source.
 12. A unit for adjustinghumidification as claimed in claim 2, characterized in that both sidesof said multiple hollow fibers are bundled together on either of theboth sides of said exothermic member and that a bundled portion of saidmultiple hollow fibers is formed with a connector to be connected to theside of a water supply source.
 13. A unit for adjusting humidificationas claimed in claim 2, characterized in that: said exothermic member isan electrically exothermic member; and said multiple hollow fibers arebundled together on the side of an electric current supply end of saidexothermic member and that a bundled portion of said multiple hollowfibers is formed with a connector to be connected to the side of a watersupply source.
 14. A unit for adjusting humidification as claimed inclaim 2, characterized in that: said exothermic member is anelectrically exothermic member; and said multiple hollow fibers arebundled together on the side opposite to an electric current supply endside of said exothermic member and that a bundled portion of saidmultiple hollow fibers is formed with a connector to be connected to theside of a water supply source.
 15. A unit for adjusting humidification,characterized in that a humidifying structural body that is structuredby a number of hollow fibers provided on an outer surface of anexothermic member and each having a peripheral wall with minute openingseach of which is large enough to allow water vapor to permeatetherethrough yet small enough to fail to permeate water therethrough;and that said humidifying structural body is disposed in a shortconnection tube so as to be detachably connected to a tube to beconnected thereto.
 16. A unit for adjusting humidification as claimed inclaim 15, characterized in that: said short connection tube is astraight tube; and said humidifying structural body is disposed so as tobe extendable in a direction parallel to an axial direction of saidshort connection tube.
 17. A unit for adjusting humidification asclaimed in claim 16, characterized in that: a mounting flange is mounteddetachably on said short connection tube; and said humidifyingstructural body is mounted on said mounting flange so as to beextendable in a direction parallel to an axial direction of said shortconnection tube when said mounting flange is mounted on said shortconnection tube.
 18. A unit for adjusting humidification as claimed inclaim 15, characterized in that: said short connection tube is agenerally L-shaped tube; and a one end portion of said humidifyingstructural body is held by a tube portion on a one side of said shortconnection tube in a region where the one end portion of the humidifyingstructural body faces a sectional surface of a path of a tube portion onthe other side of the short connection tube; and the other end side ofthe humidifying structural body extends in a direction parallel to theaxial direction of the tube portion on the other side of the shortconnection tube in the tube portion on the other side thereof.
 19. Aunit for adjusting humidification as claimed in claim 15, characterizedin that: said humidifying structural body is of an inner-outer doubletube structure with an outer tube disposed on the outer side thereof andan inner tube disposed on the inner side thereof.
 20. A unit foradjusting humidification as claimed in claim 15, characterized in thatsaid humidifying structural body is accommodated in its entirety in saidshort connection tube.
 21. A unit for adjusting humidification,characterized in that a humidifying structural body is structured by anumber of hollow fibers provided on an outer surface of an exothermicmember and each having a peripheral wall with minute openings each ofwhich is large enough to allow water vapor to permeate therethrough yetsmall enough to fail to permeate water therethrough; and that saidhumidifying structural body is held at a mounting tube to be mounted ona pipe to be humidified.
 22. A unit for adjusting humidification asclaimed in any one of claims 1 to 21, characterized in that saidexothermic member and said multiple hollow fibers are inserted tightlyinto an extendable mesh cover tube.
 23. A unit for adjustinghumidification as claimed in any one of claims 1 to 22, characterized inthat said unit for adjusting humidification is disposed in an intakecircuit of an artificially respiratory device for humidifying intakegases.
 24. A humidifying unit for an artificially respiratory device,characterized in that: a unit for adjusting humidification is structuredby an exothermic member provided on an outer surface thereof with anumber of hollow fibers each having a peripheral wall with minuteopenings each of which is large enough to allow water vapor to permeatetherethrough yet small enough to fail to permeate water therethrough;and that said unit for adjusting humidification is disposed in an intakecircuit and a water supply source is communicated with said multiplehollow fibers in said unit for adjusting humidification.
 25. A methodfor the preparation of a unit for adjusting humidification,characterized by: preparing a multiple hollow fibers gathering with saidmultiple hollow fibers connected integrally in a sheet form so as tomake the axis of each of said multiple hollow fibers nearly parallel toeach other, said multiple hollow fibers each having a peripheral wallwith minute openings each being large enough to allow water vapor topermeate therethrough yet small enough to fail to permeate watertherethrough; and winding said multiple hollow fibers gathering aroundan exothermic member in a form of a rod so as to make an axial directionof each of said multiple hollow fibers nearly parallel to the axis ofsaid exothermic member.
 26. A method for the preparation of a unit foradjusting humidification as claimed in claim 25, characterized by:folding said multiple hollow fibers gathering in the middle of saidmultiple hollow fibers gathering in a direction in which said multiplehollow fibers extend; and winding said exothermic member with saidfolded multiple hollow fibers gathering.
 27. A method for thepreparation of a unit for adjusting humidification as claimed in claim26, characterized by winding said multiple hollow fibers gathering at anend portion thereof on its path opening side and forming a bundledportion with a connector to be connected to the side of a water supplysource.
 28. A method for the preparation of a unit for adjustinghumidification, characterized by: preparing a multiple hollow fibersgathering with said multiple hollow fibers connected integrally in asheet form so as to make the axis of each of said multiple hollow fibersnearly parallel to each other, said multiple hollow fibers each having aperipheral wall with minute openings each being large enough to allowwater vapor to permeate therethrough yet small enough to fail topermeate water therethrough; and winding said multiple hollow fibersgathering around an exothermic member in a form of a rod in a spiralmanner.
 29. A method for the preparation of a unit for adjustinghumidification as claimed in claim 28, characterized by winding saidmultiple hollow fibers gathering in the form of a sheet around saidexothermic member starting with a one end portion of said exothermicmember to the other end portion of said exothermic member and thenturning back to the one end portion thereof and locating the both endportions of said multiple hollow fibers gathering at the one end portionof said exothermic member.
 30. A method for the preparation of a unitfor adjusting humidification as claimed in any one of claims 25 to 29,characterized by tightly inserting said multiple hollow fibers gatheringand said exothermic member into an extendable mesh cover tube afterwinding said multiple hollow fibers gathering around said exothermicmember.